There are many groups forecasting the 2020 Presidential Election using (primarily) polls based models. FiveThirtyEight run by Nate Silver and The Economist run by G Elliott Morris.

Both FiveThirtyEight and The Economist have published probabilities for each state in the 2020 Presidential Election.

Which forecasts will prove to be more accurate?

Will 538 outperform The Economist forecasting the 2020 Presidential Election?

To compare, we will score each set of predictions using a Brier score averaged over all N=51 races, computed as

$$S = \frac{1}{N}\sum_{i=1}^{N}\sum_{j=1}^{M}(p_{ij}−o_{ij})^2$$

where $j$ enumerates the $M_i$ possible outcomes (i.e. possible winners) in the $i$th race out of N, where $p_{ij}$ is the forecast probability of candidate $j$ winning the $i$th race, and $o_{ij}$ is assigned 1 if candidate $j$ wins the $i$th race, and 0 otherwise.

For example, if The Economist assigned 52% to Trump and 48% to Biden in Texas and if Trump won then The Economist would achieve a Brier Score of $$S=(0.52−1)^2+(0.48−0)^2=0.4608$$

A lower Brier score is better, with perfect predictions corresponding to S=0.

This question resolves positively if the Brier score for the 51 races is lower for 538's probabilities than for The Economist's probabilities. We will download each model's "model outputs" from their respective websites at 1400 UTC 02-Nov-2020

To obtain the 538 probabilities we will download the CSV from here and take the winstate_inc for Republicans and winstate_chal for Democrats in each state. (Ignoring congressional district specific probabilities)

To obtain The Economist's probabilities we will download the model outputs zip here, and use the values from the state_averages_and_predictions_topline.csv file